Air flow control valve

ABSTRACT

A control valve assembly for regulating the flow of air to a sandblasting hood is described. The control valve assembly includes a valve housing defining an inlet and outlet passageway, and a diametrically slotted valve stem which is rotatably received within the housing, intermediate the passageways. An air bleed path in communication with the inlet and outlet passageways provides for the maintenance of a minimum flow of air through the assembly. Air flow regulation is afforded by rotation of the valve stem, 90* rotation required to open the valve from the closed position. A rotatable control knob, spring-biasedly mounted to the housing concentric to the stem, is provided which when axially displaced from the housing engages the valve stem for rotation.

[ Nov. 20, 1973 24,801 1909 Great Britain..... 251/96 ABSTRACT to asandblasting hood is described. The control valve g an inlet allyslotted in communication with the inlet and outlet passageehe ...w. m hm w w d a mm n n W 08 whm m y S u S g 0.10 .l m ,h F .mme m beh 1 m a wn m m m D Wt... 7 A odn 1 o mm m mam l n P m l 3 1 C t r 5 2 col 7 .mm 0ti 1 6 5 a t ne m m| 1 wh w m mminoudii Primary Examiner-ArnoldRosenthal Attorney-Townsend and Townsend A control valve assembly forregulating the flow of air assembly includes a valve housing definin andoutlet passageway, and a diametric valve stem which is rotatablyreceived within the housing, intermediate the passageways. An air bleedpath ways provides for the maintenance of a minimum flow of air throughthe assembly. Air flow regulation is afforded by rotation of the valvestem, 90 rotation required to open the valve from the closed position. A

Inventor: Herbert A. Raschke, Greenbrae,

Calif.

Assignee: E. D. Bullard Company, Sausalito,

Calif.

May 19, 1971 137/625.32, 251/96, 251/287, 251/292 Fl6k 5/02, Fl6k 5/12251/292, 96, 287; l37/625.32, 599.1

References Cited UNITED STATES PATENTS United States Patent 1 RaschkeAIR FLOW CONTROL VALVE [22] Filed:

[21] Appl. No.: 146,576

[51] Int.

[58] Field of Search....................

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INVENTOR. HERBEET A QAGCHKE mil Patented Nov. 20, 1973 3,773,080

is Sheets-Sheet INVENTOR. HEQBEQT A. QAfDCHKE With the air flow controlvalves presently employed I in sandblasting operations, it is quitepossible for the hood wearer to completely cut off the fiow of air tothe hood either by intentionally or accidentally closing the valve. Itis also likely during the course of sandblasting operations that thehood wearer will inadvertently brush against objects at the work site.If the valve is carried on the wearers belt, as is commonly the case, ittoo will brush against these same objects possibly to effectuate achange in the valve setting. It is an object of this invention toprovide an air flow control valve which suffers none of theabove-mentioned drawbacks.

Accordingly, it is one object of this invention to provide an air flowcontrol valve assembly for regulating the flow of air to a sandblastinghood which will insure the maintaining of a minimum flow of air to thehood no matter what the setting of the valve. This object is achieved byproviding in a valve assembly including a housing having axially alignedinlet and outlet passageways and a valve chamber intermediate saidpassageways which receives a valve stem, a channel in communication withsaid passageways to define an air bleed path. The air bleed path permitsa limited amount of air to bypass the valve stem and thus insures themaintenance of a minimum flow of air to the hood regardless of the valvesetting.

It is another object of this invention to construct an air flow controlvalve assembly as described above so that the selected air flow ratewill not inadvertently be altered by the wearer of the sandblasting hoodas he brushes against objects at the work site. This object iseffectuated by providing a rotatable control knob, spring biased towardsthe valve housingfor regulating the valve setting. The knob, whendisplaced from a first, unengaged position abutting the valve housing,to a' second, engaged position, outward from the valve housing, engagesthe valve stem for rotation. In the unengaged position, the knob is freeto rotate without effecting the valve setting.

If the knob is brushed against objects at the work site, though it mayrotate, the valve setting and thus the air flow rate, will remainunaltered. Further, as the knob must be pulled outwardly from the valvehousing against the force of the spring for engagement, the chance ofaccidental displacement to the engaged position is all but eliminated.

It is a still further object of this invention to be able to adjust theflow of air through the above-described valve assembly between a minimumand a maximum flow rate by a limited rotation of the valve stem. Thisobject is achieved by providing a cylindrical valve stem intermediatethe inlet andoutlet passageways of the valve which has an openingextending diametrically therethrough. When the opening is aligned withthe inlet and outlet passageways, an air flow path is definedtherebetween. Closure of the air flow path is effectuated by limitedrotation of the valve stem, about rotation required for full closure.

It is a further object of this invention to provide a low-cost air flowcontrol valve which can be fabricated from parts designed for easycasting and quick assembly.

These and other objects will become apparent after referring to thefollowing specification and accompanying drawings, wherein:

FIG. 1 is a sectioned, perspective view of the air flow control valveassembly of this invention;

FIG. 2 is a fragmentary, sectioned top view of the inlet and outletpassageways and intermediate valve chamber, the base of the valve stemshown in section;

FIG. 3 is a sectioned detail view of the control knob assembly, thecontrol knob shown in the disengaged position;

FIG. 4 is a view similar to FIG. 3, the control knob shown in theengaged position; and

FIGS. 5, 6 and 7 are schematic views illustrating the air flow pathsthrough the valve assembly at different valve settings.

With reference to the drawings and particularly to FIG. 1, an air flowcontrol valve assembly designated generally as A is illustratedcomprising a valve housing B, a valve stem C, a valve housing cover D,and a valve control knob E. The flow of air through the valve assemblyis determined by the relative rotative position of valve stem C withinthe valve housing B. Regulation of air flow rate is afforded by rotationof the valve stem C which is in turn effectuated by rotation of controlknob E. Rotation of the stern, however, may only be effectuated when thecontrol knob is in the engaged position, pulled outwardly away from thevalve housing.

A first air hose (not shown) from an air purifier is secured to ahollow, cylindrical connecting means 10 which is force fitted into theexterior opening of air inlet passageway 12 in valve housing B. A secondair hose (not shown) attached at its one end to a sandblasting hood issecured at its other end to neck 18 of the housing. Air enteringpassageway 12 can flow through the diametric opening 16 in stem C, whenproperly aligned, and into air outlet passageway 14 and then to thesandblasting hood.

Valve stern C is rotatably received within the valve chamber defined bycylindric wall 20. The valve stem is delimited at its central portion bycylindric wall 22 which defines a bearing surface for valve stemrotation. Extending upwardly from this central portion is shank portion50, which is of reduced cross section. The lower portion of the stem,delimited by cylindric wall 24, extends across the inlet and outletports defined by passageways 12 and 14 at their termination at wall 20.This lower portion is of a reduced cross section to define an annularair bleed path between the valve stem and wall 20 of the valve chamber.Air introduced into passageway 12 will flow around the valve stem viathe air bleed path between walls 24 and 20 and into passageway 14,regardless of the valve setting, to insure a minimum airflow.

As previously noted, diametric opening 16 provided in the lower portionof the valve stem defines an air passage between passageways 12 and 14.This opening extends upwardly from the base of the stem to anintermediate point above the lowermost portion of the air passagewayports. The opening further defines a pair of feet 26 and 28 at the baseof the valve stem. Feet 26 and 28 are bounded by cylindric wall 24,interior diametrically parallel walls 30 and 31, and semi-cylindricbottom surfaces 32 and 33.

Rotation of the valve stem is limited to 90 by the particularconstruction of the base of the valve stem and valve chamber asillustrated in FIGS. 1 and 2. A pie-shaped shoulder 34 having a topsurface 36 and sidewalls 37 and 38 is provided which extends upwardlyfrom the cylindric bearing surface 40 at the base of the valve chamberto limit the rotation of the valve stem C. Bottom surface 32 of foot 26of valve stem C rests upon surface 40 and is supported by surface 40during rotation. Foot 28 is sufficiently foreshortened so that it canpass over surface 36 of shoulder 34 as shown in FIG. 1. From theposition illustrated in FIGS. l and 2, wherein the inside wall 30 offoot 26 confronts sidewall 37 of shoulder 34, the semi-cylindric surface33 of foot 28 lying above shoulder 34, stem C can be rotated clockwiseup to 90 until wall 30 of foot 26 confronts sidewall 38 of the shoulderas indicated by the broken line in FIG. 2.

It will be apparent from FIGS. 5, 6 and 7 that the amount of air flowingthrough the valve is dependent upon the relative positioning of thediametric opening 16 with respect to the ports of air passageways l2 and14. In the closed position as illustrated in FIGS. 1 and 5, wherein thediametric slot is axially perpendicular to passageways 12 and 14,limited airflow through the valve occurs, the air passing around thestem via the annular air bleed path defined between wall 20 of the valvechamber and wall 24 of the valve stem. The air flow rate may graduallybe increased by clockwise rotation of the valve stem to an intermediateflow as shown in FIG. 6. In this position, a limited amount of airpasses around the valve stem as well as through the diametric opening inthe stem. To achieve maximum airflow, the valve is fully rotated, 90from the closed position to the open position illustrated in FIG. 7. Inthis position, diametric opening 16 is axially aligned with passageways12 and 14 to allow for maximum air flow between the passageways.

The valve housing cover D, seated over housing B, retains the valve stemin place. Housing cover D is secured to the housing 8 with screws (notshown) which are received within tapped holes 62 and 44. The housingcover is formed with an opening delimited by cylindric wall 46, thatregisters with the opening of the valve chamber when the cover D is inplace over the housing. Annular shelf 48 in housing B, concentric withshaft 20, receives an O-ring (not shown). This ()-ring serves tomaintain the relative position of the stem with the valve chamber tofacilitate its rotation and prevent escape of air.

Shank portion 50 of valve stem C extends through opening 60 in housingcover D and into the interior of upstanding cylindric wall 62 on coverD, this wall being concentric to opening 60.

With reference to FIGS. 3 and 4, it will be readily apparent howrotation of control knob E will effectuate rotation of the valve stem.Control knob E, which re sides within cylindric wall 62, has a baseportion 6 3 which has an exterior cylindric surface sized for a run ningfit interior of the cylindric wall. Base portion 64 of the control knobis formed with a central bore at 66 to admit shank 50 therethrough.Control knob E also has an intermediate and concentric cylindric chamber70 and a still larger concentric and cylindric cavity 72.

At the boundary between bore 66 and chamber 70 is an annular shoulder 74that engages one end of a compression spring 76. As can be seen in FIG.3, compression spring 76 circumscribes shank portion 50. The oppositeend of spring 76 bears against a cross pin 78 which is force fitted intoa suitable diametrically extending hole at the upper end of shankportion 50. The diameter of cylindric cavity 72 is larger than thelength of pin 78 so that the pin and shank portion can rotate freelytherein.

At the boundary between cylindrical chamber 70 and cylindric cavity 72is an annular face 82. Extending from annular face 82 is one or moreprojections 84. These projections define radially extending abutmentsthat confront pin 78 when control knob E is moved axially upward againstthe force of spring 76.

The rotative position of valve stem C can be conveniently adjusted bypulling control knob E outward until pin 78 engages a projection 84 asillustrated in FIG. 4. The control knob, and thus in turn the valvestem, is rotated until the desired airflow is achieved. Release ofcontrol knob E disengages spring 76, restoring the knob to the positionshown in FIG. 3.

For facilitating movement of control knob E, the knob is provided with acircular flange 86 that has a roughened surface 88 located radiallyoutward of the outward boundary of cylindric wall 62. To prevent dustand other dirt particles from interferring in the operations of thecontrol knob, a dust cover 90 is provided which is pressure fitted inthe recess 92 of flange 86.

In a preferred embodiment, the value is designed to be capable ofdelivering at least 15 standard cubic feet per minute of air when thevalve is in the fully opened position. In the closed position, theannular bleed path permits a flow of at least 6 standard cubic feet perminute. Such minimum and maximum standard flow rates are in conformitywith the standard safety regulation requirements.

The control valve assembly is usually carried by the worker over hisworking clothing mounted on a belt. Tap holes 94 in housing B areprovided to receive attaching means for connecting the valve assembly tothe belt. Carried waist high, the control valve is maintained at acomfortable position on the workers body, where it may be easily viewedand reached to effect opening or closing.

Each part of the air flow control valve of this invention is especiallydesigned for easy casting. Virtually no finishing of the cast parts isrequired and thus fabrication costs are greatly reduced. The solemachining step involves the boring of a channel at the end of the valvestem for receiving the pin. To facilitate in the assembly of the valve,openings 68 are provided on wall 62 and openings 69 are provided oncontrol knob E. When these openings are aligned, pin 78 can be easilypassed therethrough and fitted into the hole provided in shank 54} tootherwise complete the valve assembly construction.

While one embodiment of the invention has been shown and described, itwill be obvious that other adaptations and modifications can be madewithout departing from the true spirit and scope of the invention.

What is claimed is:

I. An air flow control valve comprising:

a housing having an inlet passageway and an outlet passageway;

said housing further having an internal cylindric wall that defines acylindric valve chamber, said inlet and outlet passageways terminatingin ports in said cylindric wall, said ports being at substantially thesame position axially of the cylindric chamber; cylindric valve bodydisposed in said chamber and including means for establishing in airflow path between said inlet passage and outlet passage that affordsairflow between said passages in proportion to the relative rotativeposition of said valve body, said valve body having an upper shankportion that extends from said housing through an opening in saidhousing, engaging means diametrically projecting from the shank near theend thereof;

a rotatable cylindric control knob mounted to said housing concentricwith said shank, and axially displaceable from said housing, said knobhaving an aperture at its base through which the valve shank extends,said knob further having a first concentric cavity extending upwardlyfrom the opening at its base and a second, larger cavity extendingupwardly from said first cavity, spring means within said firstconcentric cavity of said knob and extending to said engaging means forbiasing said knob towards said valve housing;

said knob still further including an annular shelf defined between theboundary of said first and second cavity and at least one radialprojection extending from said annular shelf;

and means for axially displacing said control knob from said housing tobring the engaging means at the end of the shank into contact with saidannular shelf, whereby rotation of said knob will bring said projectioninto confronting relationship with said engaging means, and furtherrotation will induce said valve body to rotate.

2. The air flow control valve of claim 1 wherein said valve bodyincludes an intermediate cylindric portion axially remote from saidports for defining a bearing surface for rotation of said valve body insaid chamber, said valve body having a lower cylindric portion oppositesaid ports, wherein said lower cylindric portion has a diameter lessthan the diameter of said chamber to define an air bleed path betweensaid inlet and outlet passageways that is substantially constantirrespective of the rotative position of said valve body.

3. An airflow control valve assembly for regulating the flow of air to asandblasting hood comprising:

a valve housing having an inlet passageway and an outlet passageway;

a cylindric valve stem received in a cylindric valve chamber in saidhousing intermediate said passageways, said valve stem defining a pairof semicylindric feet at its base, one of said feet foreshortened so asto receive projecting means therebeneath;

an opening in said valve stem defining an air flow path between saidinlet and outlet passageways to afford air flow between said passages inproportion to the relative rotative position of said valve stem;

an air bleed path in communication with said inlet and outletpassageways for establishing a minimum flow of air through the valveassembly irrespective of the rotative position of said valve stem;

projecting means comprising a raised shoulder having side walls whichextend upwardly from the base of the valve chamber, said rotation of thevalve body within the chamber limited by said shoulder side wallsthrough or less;

and control means comprising a cylindrical control knob concentricallymounted to the valve housing, and axially displaceable along its lengthto engage a projection in said valve stem, whereby when so engaged,rotation of said knob induces rotation of said valve stem.

4. An airflow control valve comprising a housing defining an inletpassage and an outlet passage, said housing further having an internalcylindric wall that defines a cylindric valve chamber having a circularbase, said inlet and outlet passages terminating in ports in saidcylindric wall, said ports being in substantially the same positionaxially as the cylindric chamber;

a valve body disposed in said chamber and having a first cylindricportion axially remote from said ports for defining a bearing surfacefor rotation of said valve body within said chamber, said valve bodyhaving a second cylindric portion opposite said ports, said secondcylindric portion having a diameter less than the diameter of said boreto define an air bleed passage between said inlet passage and saidoutlet passage that is substantially constant in volume irrespective ofthe positioning of said valve body;

a shoulder having upstanding side walls extending from said circularbase of said cylindric valve chamber, said shoulder defining a 90segment of said base; and

a diametric slot extending from the base of said second cylindricportion across the ports of said inlet and outlet passages to establishan airflow passage between said passages, said diametric slot furtherdefining a pair of feet of substantially semi-circular cross-section,one of said feet supported on the surface of the said circular base, theother of said feet foreshortened to receive said shoulder therebeneathwhereby rotation of said valve body within said valve chamber is limitedby the upstanding side walls of said shoulder.

5. The air flow control valve of claim 4 wherein said valve body has anupper shank portion which extends from said housing through an openingin said housing, engaging means provided on said shank near its end, andsaid means for afiording rotation of said valve body comprises arotatable cylindric control knob mounted to said housing concentric withsaid valve shank, and axially displaceable from said housing, said knobhaving an aperture at its base through which the valve shank extends,and further having a first concentric cavity extending upwardly from theopening at its base, spring means within said first concentric cavity,said means circumscribing said shank, and extending to said engagingmeans, for biasing said knob toward said housing, and a second largercavity concentric with said first cavity, the boundary between saidfirst and second cavity defining an annular shelf, at least one radialprojection extending from said shelf, and means for axially displacingsaid control knob from said housing to bring the engaging meansproximate the end of the valve shank to bear against the annular face,whereby said projection is brought into contronting relationship withsaid engaging means by rotation of said knob, further rotation of saidknob inducing rotation of said body.

1. An air flow control valve comprising: a housing having an inletpassageway and an outlet passageway; said housing further having aninternal cylindric wall that defines a cylindric valve chamber, saidinlet and outlet passageways terminating in ports in said cylindricwall, said ports being at substantially the same position axially of thecylindric chamber; a cylindric valve body disposed in said chamber andincluding means for establishing in air flow path between said inletpassage and outlet passage that affords airflow between said passages inproportion to the relative rotative position of said valve body, saidvalve body having an upper shank portion that extends from said housingthrough an opening in said housing, engaging means diametricallyprojecting from the shank near the end thereof; a rotatable cylindriccontrol knob mounted to said housing concentric with saiD shank, andaxially displaceable from said housing, said knob having an aperture atits base through which the valve shank extends, said knob further havinga first concentric cavity extending upwardly from the opening at itsbase and a second, larger cavity extending upwardly from said firstcavity, spring means within said first concentric cavity of said knoband extending to said engaging means for biasing said knob towards saidvalve housing; said knob still further including an annular shelfdefined between the boundary of said first and second cavity and atleast one radial projection extending from said annular shelf; and meansfor axially displacing said control knob from said housing to bring theengaging means at the end of the shank into contact with said annularshelf, whereby rotation of said knob will bring said projection intoconfronting relationship with said engaging means, and further rotationwill induce said valve body to rotate.
 2. The air flow control valve ofclaim 1 wherein said valve body includes an intermediate cylindricportion axially remote from said ports for defining a bearing surfacefor rotation of said valve body in said chamber, said valve body havinga lower cylindric portion opposite said ports, wherein said lowercylindric portion has a diameter less than the diameter of said chamberto define an air bleed path between said inlet and outlet passagewaysthat is substantially constant irrespective of the rotative position ofsaid valve body.
 3. An airflow control valve assembly for regulating theflow of air to a sandblasting hood comprising: a valve housing having aninlet passageway and an outlet passageway; a cylindric valve stemreceived in a cylindric valve chamber in said housing intermediate saidpassageways, said valve stem defining a pair of semi-cylindric feet atits base, one of said feet foreshortened so as to receive projectingmeans there-beneath; an opening in said valve stem defining an air flowpath between said inlet and outlet passageways to afford air flowbetween said passages in proportion to the relative rotative position ofsaid valve stem; an air bleed path in communication with said inlet andoutlet passageways for establishing a minimum flow of air through thevalve assembly irrespective of the rotative position of said valve stem;projecting means comprising a raised shoulder having side walls whichextend upwardly from the base of the valve chamber, said rotation of thevalve body within the chamber limited by said shoulder side wallsthrough 90* or less; and control means comprising a cylindrical controlknob concentrically mounted to the valve housing, and axiallydisplaceable along its length to engage a projection in said valve stem,whereby when so engaged, rotation of said knob induces rotation of saidvalve stem.
 4. An airflow control valve comprising a housing defining aninlet passage and an outlet passage, said housing further having aninternal cylindric wall that defines a cylindric valve chamber having acircular base, said inlet and outlet passages terminating in ports insaid cylindric wall, said ports being in substantially the same positionaxially as the cylindric chamber; a valve body disposed in said chamberand having a first cylindric portion axially remote from said ports fordefining a bearing surface for rotation of said valve body within saidchamber, said valve body having a second cylindric portion opposite saidports, said second cylindric portion having a diameter less than thediameter of said bore to define an air bleed passage between said inletpassage and said outlet passage that is substantially constant in volumeirrespective of the positioning of said valve body; a shoulder havingupstanding side walls extending from said circular base of saidcylindric valve chamber, said shoulder defining a 90* segment of saidbase; and a diametric slot extending from the base of said secondcylindric portion acrosS the ports of said inlet and outlet passages toestablish an airflow passage between said passages, said diametric slotfurther defining a pair of feet of substantially semi-circularcross-section, one of said feet supported on the surface of the saidcircular base, the other of said feet foreshortened to receive saidshoulder therebeneath whereby rotation of said valve body within saidvalve chamber is limited by the upstanding side walls of said shoulder.5. The air flow control valve of claim 4 wherein said valve body has anupper shank portion which extends from said housing through an openingin said housing, engaging means provided on said shank near its end, andsaid means for affording rotation of said valve body comprises arotatable cylindric control knob mounted to said housing concentric withsaid valve shank, and axially displaceable from said housing, said knobhaving an aperture at its base through which the valve shank extends,and further having a first concentric cavity extending upwardly from theopening at its base, spring means within said first concentric cavity,said means circumscribing said shank, and extending to said engagingmeans, for biasing said knob toward said housing, and a second largercavity concentric with said first cavity, the boundary between saidfirst and second cavity defining an annular shelf, at least one radialprojection extending from said shelf, and means for axially displacingsaid control knob from said housing to bring the engaging meansproximate the end of the valve shank to bear against the annular face,whereby said projection is brought into contronting relationship withsaid engaging means by rotation of said knob, further rotation of saidknob inducing rotation of said body.